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Bureau of Mines Information Circular/1985 



Mercury Availability— Market 
Economy Countries 

A Minerals Availability Appraisal 



By C. P. Mlshra, D. R. Wllburn, D. Q. Hartos, 
C. D. Sheng-Fogg, and R. C. Bowyer 




UNITED STATES DEPARTMENT OF THE INTERIOR 



I75J 

**/NES 75TH A^ 



t ' > , lluM*« rfW^ ) 



Information Circular 9038 



/ 



Mercury Availability— Market 
Economy Countries 

A Minerals Availability Appraisal 



By C. P. Mlshra, D. R. Wllburn, D. G. Hartos, 
C. D. Sheng-Fogg, and R. C. Bowyer 




UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 
Robert C. Horton, Director 




£^ 



As the Nation's principal conservation agency, the Department of the 
Interior has responsibility for most of our nationally owned public lands 
and natural resources. This includes fostering the wisest use of our land 
and water resources, protecting our fish and wildlife, preserving the 
environmental and cultural values of our national parks and historical 
places, and providing for the enjoyment of life through outdoor recreation. 
The Department assesses our energy and mineral resources and works to 
assure that their development is in the best interests of all our people. The 
Department also has a major responsibility for American Indian reserva- 
tion communities and for people who live in island territories under U.S. 
administration. 




Library of Congress Cataloging in Publication Data 



Main entry under title 

Mercury availability — market economy countries 

(Bureau of Mines information circular; IC 9038) 

Bibliography: p. 18 

Supt. of Docs, no.: I 28.27: 

1. Mercury industry and trade. 2. Mercury mines and mining. 3. Strategic materials. 4. 
Market surveys. I. Mishra, C. P. (Chamundeshawari P.) II. Series: Information circular (United 
States. Bureau of Mines); 9038. 

TN295.U4 [HD9539.M42] 622 s [338.2'7454] 85-600116 



For sale by the Superintendent of Documents, U.S. Government Printing Office 
Washington, DC 20402 



- 



PREFACE 

In order to assess the availability of strategic and critical nonfuel minerals, the 
Bureau of Mines Minerals Availability Program identifies, collects, compiles, and 
evaluates information on producing, developing, and explored deposits and mineral proc- 
essing plants worldwide. Objectives are to classify domestic and foreign resources, to 
identify by cost evaluation resources that are reserves, and to prepare analyses of mineral 
availabilities. 

This report is one of a continuing series of reports that analyze the availability of 
minerals from domestic and foreign sources. Questions about the Minerals Availability 
Program should be addressed to Chief, Division of Minerals Availability, Bureau of 
Mines, 2401 E Street NW., Washington, DC 20241. 






CONTENTS 



Page 

Preface iii 

Abstract 1 

Introduction 2 

Acknowledgments 2 

Commodity overview 2 

Consumption and uses 2 

Substitutes 2 

Recycling 3 

Production history 3 

Market and pricing history 4 

Identification and selection of deposits 5 

Deposit evaluation procedures 7 

Geology 8 

Resources 9 

Domestic resources 9 

Foreign resources 10 



Page 

Extraction technology 11 

Mining 11 

Beneficiation 12 

Environmental considerations 12 

Capital and operating costs 13 

Capital costs 13 

Operating costs 13 

Mercury availability 15 

Total availability 15 

Annual availability 15 

Factors affecting availability 17 

Conclusions 17 

References 18 

Appendix A 18 

Appendix B 18 



ILLUSTRATIONS 

1. Mercury use distribution 3 

2. Summary of production and consumption of mercury ! 4 

3. Mercury market price history, 1900 to present 5 

4. Location map of evaluated deposits 6 

5. Bureau of Mines-U.S. Geological Survey system for classification of mineral resources 7 

6. Flowsheet of evaluation procedure 7 

7. Distribution of demonstrated domestic mercury resources 10 

8. Flowsheet of typical mercury beneficiation process 12 

9. Annual availability from producing deposits at various prices 15 

10. Annual availability from nonproducing deposits at various prices 16 

TABLES 



1. Summary of domestic and foreign mercury demand forecasts 3 

2. Deposits selected for evaluation 6 

3. Demonstrated mercury resources as of January 1984 9 

4. Estimated operating costs for principal mercury deposits, per metric ton of ore 14 

5. Estimated operating costs for principal mercury deposits, per flask of recoverable mercury 14 

6. Total resource availability 15 



VI 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 



°c 


degree Celsius 


cm 


centimeter 


h 


hour 


km 


kilometer 


L 


liter 


lb 


pound 


m 


meter 


m 3 


cubic meter 



mg milligram 

mg/L milligram per liter 

mg/m 3 milligram per cubic meter 

\xg microgram 

/^g/m 3 microgram per cubic meter 

mt metric ton 

pet percent 

yr year 



MERCURY AVAILABILITY— MARKET ECONOMY COUNTRIES 
A Minerals Availability Appraisal 



By C. P. Mishra, 1 D. R. Wilburn, 2 D. G. Hartos, 3 
C. D. Sheng-Fogg, 2 and R. C. Bowyer 4 



ABSTRACT 

The Bureau of Mines investigated the availability of mercury from 22 deposits in 
market economy countries. The 15 significant deposits evaluated have demonstrated 
resources of appi-oximately 25 million metric tons of ore containing 5.3 million flasks 
of mercury and account for more than 85 pet of the demonstrated resources for market 
economy countries. Using data gathered as part of its Minerals Availability Program, 
the Bureau determined the mercury production potential of each deposit. 

At a January 1984 mercury market price of $300 per flask, the deposits evaluated 
could economically produce an estimated 2.5 million flasks of mercury from six mines 
operating at the time of this study; no mercury is available at this price from nonproduc- 
ing operations. At $600 per flask, approximately 4.5 million flasks of mercury are 
available. For production costs up to $300 per flask, operating mines could supply mer- 
cury at the current production rate of 114,000 flasks per year until 1988, when the 
amount of mercury available from these deposits would decrease. This decline could 
be offset by the development of resources currently reported at the identified level (17 
million flasks) at much higher production costs. 

'Supervisory physical scientist. 

'Physical scien; 

'Physical scientist inow with Office of Surface Mining. Pittsburgh, PA). 

"Geologist. 

Minerals Availability Field Office, Bureau of Mines, Denver, Co. 



INTRODUCTION 



Mercury's unusual combination of physical and 
chemical properties gives it an industrial and economic im- 
portance much greater than the size of its production would 
indicate. It is considered by the Bureau of Mines to be a 
critical commodity for the United States owing to its ex- 
tensive use in a variety of industrial, scientific, and military 
applications, many of which have few satisfactory 
substitutes. Despite its importance, significant production 
is geologically restricted to a limited number of areas, many 
of which have ceased production in recent years as a result 
of depressed market conditions. 

Production in the United States, Yugoslavia, and Italy 
has declined sharply, while mercury mines in the U.S.S.R. 
and China have achieved a greater degree of world prom- 
inence. In 1983, the United States produced 50 pet of its 
consumption from primary sources of mercury and 28 pet 
from secondary sources. The remaining 22 pet was imported 
or supplied from Government stockpiles, (12). s Most of the 
current domestic production comes from one mine which 
has an expected life of 5 to 8 yr. 

Owing to the critical nature of mercury and its limited 



sources of supply, it is important to examine the availability 
of mercury from both present and potential sources. The 
Bureau's primary objectives for this study were to evaluate 
the availability of mercury from market economy countries 6 
and to assess domestic mercury resources in relation to 
those of other market economy countries. These availability 
determinations can be used in the development or modifica- 
tion of a domestic minerals policy and can be of direct 
benefit to programs concerned with mineral stockpile 
assessment, minerals exploration, extraction technology 
research, tax restructing, substitute mineral studies, and 
land utilization. No comprehensive world mercury resource 
studies have been conducted since the late 1950's, and no 
recent comprehensive availability studies on mercury have 
been published. This study consolidates past work (9, 11) 
with more recent data from numerous sources and sum- 
marizes available industry data on mercury as of January 
1984. Current and potential availability data for mercury 
are presented in a series of supply curves with appropriate 
explanatory text. 



ACKNOWLEDGMENTS 



Domestic production and cost data for the deposits 
assessed in this study were developed at Bureau of Mines 
Field Operations Centers at Denver, CO, and Spokane, WA. 
The following personnel contributed data used in this study: 
Alan G. Hite, physical scientist, Intermountain Field Opera- 
tions Center, Denver, CO, and David A. Benjamin, George 
A. Gale, Nathan T. Lowe, Michael Sokaski, and Thomas 
M. Sweeney, all at the Western Field Operations Center, 
Spokane, WA. 



Production and cost data for other countries were col- 
lected through a Bureau of Mines contract with Pincock, 
Allen, & Holt, Inc. of Tucson, AZ. Selected resource and pro- 
duction data were provided by Linda Carrico, Bureau of 
Mines commodity specialist, Washington, DC. Technical 
assistance was provided by Victor Botts, manager, Nevada 
Operations, Placer U.S., Inc. 



COMMODITY OVERVIEW 



CONSUMPTION AND USES 

Mercury, also known as quicksilver, is one of the few 
metals that is liquid at ordinary temperatures. Other im- 
portant properties that influence its marketability include 
its high density, uniform volume expansion, high electrical 
conductivity, ability to alloy readily, high surface tension, 
chemical stability, and toxicity of its compounds. 

Mercury's unique characteristics have enabled it to be 
used historically in a wide variety of applications, including 
electrical apparatus, industrial and control instrumenta- 
tion, agriculture, pharmaceuticals, paints, pigments, elec- 
trolytic preparation of chlorine and caustic soda, and dental 
supplies. Owing to the toxic nature of mercury vapor and 
certain compounds, its use in some of these areas has been 
restricted in recent years. Since world mercury use patterns 
are not available, the domestic uses of mercury are outlined 
in figure 1. 

Worldwide consumption data by end use are not 
available. However, it is estimated that approximately 
220,000 flasks of mercury were consumed in 1983 (2). De- 



mand will most likely increase more rapidly in developing 
countries than in industrialized nations. Based upon an- 
ticipated growth in world mercury consumption, the 
forecasted world demand in 2000 is estimated to be between 
212,000 and 356,000 flasks. The most probable demand is 
241,000 flasks in 1990 and 276,000 flasks in 2000, based 
on an average annual growth rate of 1.4 pet (2). This growth 
rate is based on best available published data; recent data 
indicates that the growth rate may in fact be lower. A sum- 
mary of anticipated mercury demand is presented in table 1. 



SUBSTITUTES 

Other materials may be substituted for mercury in selected 
application, but for those uses that require mercury's 
unusual combination of physical and chemical properties, 
there have been few satisfactory substitutes. Nickel- 
cadmium batteries may replace mercury batteries in cer- 



5 Italicized numbers in parentheses refer to items in the list of references 
preceding the appendix. 



"Market economy countries, as defined by the Bureau of Mines include all 
countries except the centrally planned economy countries of Albania, 
Bulgaria, China, Cuba, Czechoslovakia, the German Democratic Republic, 
Hungary, Kampuchea, North Korea, Laos, Mongolia, Poland, Romania, the 
U.S.S.R., and Vietnam. 



Control instalments 




Figure 1.— Mercury use distribution. 



Table 1.— Summary of domestic and foreign mercury demand 
forecasts, 76-pound flasks (2) 



Probable 



2000 



1983 



1990 



2000 



Low 



High 



Domestic: 

Primary 35.664 42.000 39.000 14.000 64.000 

Secondary 13,474 6,000 7,000 3,000 12.000 

Foreign: 

Pnmary 152.000 170.000 200,000 164,000 236,000 

Secondary 19,000 23.000 30,000 31,000 44.000 

World: 

Pnmary 187.664 212,000 239,000 178,000 300.000 

Secondary 32.474 29.000 37,000 34,000 56,000 

Total 220.138 241.000 276.000 212,000 356,000 



tain electrical applications. Solid state control devices can 
replace mercury in some control instrumentation. In chlor- 
alkali processing, the diaphragm cell is gradually replac- 
ing the mercury- cell. Sodium vapor lamps are widely used 
instead of mercury vapor lamps for lighting. Sulfa drugs, 
iodine, other antiseptics and disinfectants are possible mer- 
cury* substitutes in pharmaceutical use. Porcelain and 
plastic replace mercury in some dental uses. Plastic and cop- 
per oxide paints have been used to protect ship hulls, and 
organic mildewcides are being substituted in latex paints. 



RECYCLING 

Environmental concerns have led to increased use of 
recycling of scrap mercury at the expense of prime virgin 
material. Secondary mercury is generally 99.99 pet pure 
and produced by redistillation. Virtually all mercury can 
be reclaimed from mercury cell-chlor-alkali plants, electrical 
apparatus, and control instruments when plants or equip- 
ment are dismantled or scrapped. Reduced demand for 
chlorine has closed a number of chlor-alkali plants 
worldwide; conversion of these plants to other processes has 
recently released a significant quantity of secondary mer- 
cury on the market. The importance of recycled mercury 
is illustrated by current domestic consumption patterns, 
where secondary mercury accounted for 28 pet of the 
reported domestic consumption in 1983 (12). 



PRODUCTION HISTORY 

For more than 2,300 yr, mercury has been recovered 
from cinnabar (HgS) deposits throughout the world. While 
mercury is found in varying amounts in most rocks, 
recoverable concentrations of mercury are more scarce. 
Prior to 1850, three mining districts dominated world mer- 
cury production: Almaden in Spain, Idria in Yugoslavia, 
and Santa Barbara in Peru. Four major districts, Monte 
Amiata in Italy, California in the United States, Almaden, 
and Idria, have supplied most of the world's mercury pro- 
duction since 1850. 

The Almaden area has produced mercury since 400 B.C. 
Records dating back to 1500 show production of over 7 
million flasks of mercury through 1957 from Almaden (9), 
or almost three times as much as that of any other area 
of the world. Currently, about 23 pet of world production 
comes from the Almaden district. 

Mercury in the Idria district of Yugoslavia was first 
discovered about 1470. Since then, the Idria Mine has pro- 
duced over 2.5 million flasks of mercury through 1957 and 
ranked second in the world for total mercury production. 
The Idria Mine was closed from 1977 to 1982 owing to a 
depressed market. 

The Santa Barbara district, which included the Santa 
Barbara Mine in Peru, was for many years the world's 
leading mercury producer. From 1566 to 1790, this district 
produced 1.47 million flasks of mercury. By the end of the 
18th century, reserves were almost depleted; since then only 
negligible amounts of mercury have been produced. In 
terms of total output, Santa Barbara has been ranked as 
the fourth largest mercury mine in the world (9). 

Almost all Italian mercury production came from the 
Monte Amiata district. While mercury occurrences in this 
area were known and mined by the Etruscans as long ago 
as 400 B.C., modern production did not start until 1868. 
The extent of the mineralization was such that as reserves 
in individual mines were depleted, other mines in adjacent 
areas opened up for production. Italy led the world in mer- 
cury production in the 1920's, when the Idria Mine was part 
of Italian territory. Between 1900 and 1957, Italian mer- 
cury production from the Monte Amiata district exceeded 
2 million flasks. The Abbadia San Salvatore Mine, the 
northernmost producing mine in the district, was the larg- 
est and most consistent producer in Italy in recent years, 
until its closure in 1982 due to economic factors. 

Production of mercury in the United States began in 
California about 1850. California mines produced about 80 
pet of the total mercury mined in the United States from 
1850 to 1981, and almost all of the domestic mercury mined 
from 1850 to 1898. 

Much of California's mercury production came from two 
mines, the New Almaden Mine and New Idria Mine. The 
New Almaden Mine was the first mine in North America 
to produce mercury; more than 90 pet of its production oc- 
curred between 1850 and 1900. Earliest production came 
from ore averaging 37 pet Hg. At the height of production 
in 1865, ore grade had dropped to 18 pet, and by 1895 the 
grade was less than 1 pet. During its life, New Almaden 
produced over 1.05 million flasks of mercury (11). The New 
Idria Mine opened in 1853, but unlike New Almaden, two- 
thirds of its production occurred after 1900. The New Idria 
Mine produced over 600,000 flasks of mercury until its 
closure in 1972 (/). 

In recent years, declining ore grade, low prices, and lack 
of demand have forced the closure of all California mercury 



350 



300- 




1925 



1935 1945 1955 1965 

Figure 2.— Summary of production and consumption of mercury. 



1975 



1985 



mines. Domestic mercury needs have been partially met by 
the opening in 1975 of the McDermitt Mine in Nevada. 

Figure 2 summarizes the recent history of world mer- 
cury production. Domestic production and consumption for 
the same period are shown for comparison purposes. 

Mercury production reached a high during World War 
II, but while world production managed to recover from the 
postwar decline in production, U.S. production never fully 
recovered. As shown in figure 2, the United States supplied 
approximately 14 pet of world production in 1960; by 1970, 
U.S. production had fallen to 10 pet of the world's total. 
Declining ore grade and high production costs, particularly 
for California operations, never allowed domestic produc- 
tion to meet the growing U.S. demand. In 1960, U.S. pro- 
duction met 71 pet of domestic consumption; by 1970, 
domestic production was only able to meet 44 pet of con- 
sumption. Because of increasing awareness of mercury tox- 
icity, pollution, and use of substitutes since 1970, world mer- 
cury demand has decreased. U.S. production also dipped in 
the early 1970's because of increased environmental con- 
cern but stabilized in the mid-1970's owing to the emergence 
of the McDermitt Mine. At present, U.S. mine production 
is approximately 13 pet of the world mine production and 
supplies 50 pet of domestic consumption. The remainder is 
either imported or supplied by secondary domestic sources. 
While low mercury prices, increased energy and labor 
costs, and environmental problems have forced the reduc- 



tion or cessation of mercury production from market 
economy counties, mines in centrally planned economy 
(CPE) countries have achieved world prominence in recent 
years. Production in CPE countries was 20 pet of the world 
total in 1960, 25 pet in 1970, and 43 pet in 1980. In 1983, 
production from CPE countries amounted to 46 pet of world 
production of mercury. 



MARKET AND PRICING HISTORY 

The product of most mercury mines is cinnabar, which 
is commonly processed to recover 99.9-pct-pure mercury 
metal (prime virgin). Mercury is sold on the basis of 76-lb 
flasks. This unit of measure originated in Spain and has 
been accepted as a worldwide standard since Spain has been 
the world's leading mercury producer for centuries. 

There are no uniform market specifications for mercury 
(6). The average New York dealers' price for prime virgin 
mercury as of January 1984 was $304.48 per flask. Other 
grades are produced occasionally by multiple distillation 
or other means to reduce impurities, at a correspondingly 
higher market price. 

Mercury price has fluctuated widely because of erratic 
demand and overproduction. Domestic prices have also been 
influenced by environmental regulations, increased recycl- 
ing, and imports from large, low-cost foreign producers. A 



TOO 



600 



500 



400 



or 
a 

> 
cr 

=> 
O 

or 

UJ 



300 



200 



:■: - 



o 

1900 





1 I I 1 
KEY 


1 1 1 




/ 


1914, World Wor I 






2 


1916, British end emborgo 






3 


1918, War Industries Board attempts to stabilize price 






4 


1922, Industrial boom 






5 


1928, Spanish-Italian mercury cartel formed 






6 


1929, Stock morket crash 






7 


1932, Rumors of cartel breakup 


/22 




8 


1933, Cartel continues to sell 




9 


1936, Spanish Civil War 








10 


1937, Overimportation by United States 










II 


1939, War buildup in Europe 






- 


12 


1940, World War II 








13 


1942, OPA ceiling prices set 








14 


1944, High U.S. production 








15 


1945, Development of mercuric oxide battery 




/2 9 




16 


1948, Cortel boosts price 






17 


1950, Korean conflict, cartel disbanded, price supports instituted 


A 




Iff 


1953, Large U.S. Government purchases 


1 A 


- 


19 


1954, Oversupply, price supports reduced 








20 


1957, U.S. Government reestablishes price supports 




\/24 \ \ 




21 


1963, Italians set floor price, large mercury sales to Eastern Bloc countries 






22 


1967, Low Almoden production 








23 


1969, Pollution questions raised 




1 /25 vc \ 




24 


1971, EPA regulations proposed 






(? \ 




25 


1972, EPA bans mercury paint use, U.S. S.R. floods mercury morket . 


?K 






26 


1973, Worldwide restrictions on mercury use and discharge \/\ 


\i 






27 


1974, Creation of ASS IMER J\ 


J& 7 






28 


1976, Restricted mercury scales / 


\y 








29 


1982, Numerous mine closures ,, 18k \ 

l2 \ X f^/ 












/ Z / 5 "\ \ \ //I5 \ 

/ / 3 // 6 \ / x/ \ 








/ \ / \ 5 \\ / V 


^28 


- 












- — ^J ^% \> 

1 1 1 1 1 


i i 1 





1920 1930 1940 1950 I960 

Figure 3.— Mercury market price history, 1900 to present. 



I970 



I980 



I990 



summary of the mercury price history since 1900 is shown 
in figure 3. 

In the early 20th century, mercury demand was highest 
during periods of peak industrial activity. Prices were high 
during World War I, the 1920's industrial boom, and World 
War II, but when demand decreased, as in the postwar 
years, mercury prices decreased dramatically. By 1950, the 
price of mercury has decreased to its lowest level since the 
Depression. At that time, prices were bolstered by increased 
industrialization resulting from the Korean conflict and 
price supports instituted by the U.S. Government. During 
the mid-1960's, the mercury price rose to an all-time high 
of $570 per flask, owing in part to Italian price regulation 
and large mercury demand by Eastern Bloc countries. 
Prices in the early 1970's were influenced by weak U.S. de- 
mand, increased environmental regulation, and large 
Spanish and Italian inventories. Low prices and high min- 



ing and environmental pollution control costs led to the 
closure of many low-grade domestic and Canadian proper- 
ties. The withholding of mercury by Spanish and Italian 
producers from North American markets coincided with the 
1976 price reversal. Because of tighter market controls as 
a result of the policies of the newly created mercury pro- 
ducers association, ASSIMER, mercury prices have gradual- 
ly risen in recent years to a January 1984 price of approx- 
imately $300 per flask. In spite of this improvement, en- 
vironmental concerns continue to dampen growth in 
domestic consumption, especially in paints, agriculture, 
pharmaceuticals, and the chlor-alkali industry (12). A com- 
bination of low prices, insufficient demand, large inven- 
tories, and high production costs suspended mercury pro- 
duction at the Italian mercury mines in 1983. At present, 
the McDermitt Mine is the only primary U.S. mercury 
producer. 



IDENTIFICATION AND SELECTION OF DEPOSITS 



There are over 1,300 known mercury occurrences 
throughout the world, and many more areas with possible 
mercury content <9>. It is not feasible to perform complete 
economic analyses on all known occurrences. Of the 22 
deposits investigated in this study, the 15 deposits with the 



most significant resource potential have been evaluated. 
Depositis considered for economic evaluation have at least 
600 flasks contained mercury. Properties were selected by 
the Bureau with the aim of including key deposits that 
supply at least 85 pet of current production from market 



economy countries. Significant developing, explored, and 
past producing deposits were also included. Domestic 
deposits considered for evaluation, but not included in this 
study because they did not meet the selection criteria, are 
listed in appendix A. The 15 mercury deposits (table 2) in 
7 market economy countries selected for this study account 
for more than 85 pet of the demonstrated mercury resources 
for all market economy countries. Figure 4 shows the loca- 
tions of these deposits. Deposits in market economy coun- 
tries not included in this study are considered insignificant 
on a worldwide scale. An exception would be the Idria Mine 
in Yugoslavia, which was excluded due to the inaccessibility 
of detailed data. 



Resource estimates were made at the demonstrated 
level according to the mineral resource classification system 
developed by the U.S. Geological Survey and the Bureau 
of Mines (fig. 5) (13). Using this classification system, 
demonstrated resources are defined as the in situ measured 
plus indicated tonnages that make up the reserve base. 
Resource quantity and grade were determined from site in- 
spections, drilling data, mine workings, and sampling. The 
reserve base includes resources that are currently economic 
(reserves) and marginally economic (marginal reserves), and 
some that are currently subeconomic (subeconomic 
resources). 



Table 2.— Deposits selected for evaluation 



Deposit and location 



Ownership 



Status 1 



Mining 
type 2 



Algeria: 

Ismail 

M'Rasma 

Canada: Pinchi Lake 

Italy: 

Abbadia S. Salvatore 

Selvena 

Philippines: Palawan Quicksilver 

Spain: Almaden 

Turkey: 

Halikoy 

Karaburun-lzmir 

Karareis 

Konya Area 

United States: 

B and B Mine 

Gibraltar 

McDermitt 

Study Butte 



SONAREM (Government owned) 

..do 

COMINCO, Ltd 



SAMIM (Government owned) 

..do 

Palawan Quicksilver Mines, Inc. 
Arrayanes, S.A. (Government owned) 

Etibank (Government owned) 

Undetermined 4 

..do 

Etibank (Government owned) 



Private individual 

Undetermined 4 

Placer U.S., Inc 

Sanger Investment Co. 



p 


S 


p 


S 


N 


S-U 


N 


U 


N 


U 


N 


S 


P 


S-U 


P 3 


u 


N 


s 


N 


u 


PS 


u 


N 


s 


N 


u 


P 


s 


N 


u 



!N = not producing as of January 1984; P = producing as of January 1984. 

2 S = surface; U = underground; for deposits not producing, mining type is proposed based on past history, geology, and technology. 

Operations producing at limited rate for internal use only. 

Ownership undetermined since property either has been abandoned or is involved in litigation. 







<J™&si^P i ~' 


? 


cfc- 


.-. •■•• 




e^» o_ 


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Q/2 1 

/ 6 


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VV4 








wft>-:. ( 
































/ 


KEY 

Almaden, Spain 
















V>v 


2 


M'Rasma, Algeria 












\ A 


^ i 


3 


McDermitt, United States 












/ n 


r^Xn 




4 


Halikoy, Turkey 












' U 


~s w 


[ } 


5 


Konya Area, Turkey 














\ 


\ * 


6 


Ismail, Algeria 


















7 


Selvena, Italy 














i^-\ 


/ 


8 


Pinchi Lake, Canada 














\y 




9 


Abbadia S. Salvatore, Italy V / 












s/ 


A 


10 


Gibraltar, United States 














cr 


^J? 


II 


Karareis, Turkey 
















cr 


12 


Karaburun-lzmir, Turkey 


















13 


Palawan Quicksilver, Phili 


ppines 
















14 


Study Butte, United States 
















15 


BSB Mine, United States 






















<^L<sQ 















Figure 4.— Location map of evaluated deposits. 



Cumulative 
production 



IDENTIFIED RESOURCES 



Demonstrated 



Measured Indicated 



Inferred 



UNDISCOVERED RESOURCES 



Hypothetical 



Probability range 
(or) 



Speculative 



ECONOMIC 



MARGINALLY 
ECONOMIC 



SUB- 
ECONOMIC 



Reserve 



base 



Inferred 



reserve 



base 



+ 



-f 



Other 
occurrences 



Includes nonconventional and low-grade materials 



Figure 5.— Bureau of Mines— U.S. Geological Survey system for classification of mineral resources. 



DEPOSIT EVALUATION PROCEDURES 



Figure 6 is a flowsheet of the Bureau's Minerals 
Availability Program (MAP) evaluation process, from 
deposit identification to the development of availability 
curves. The flowsheet shows the various evaluation stages 
used in this study to assess the availability of mercury from 
individual domestic and foreign properties. 



An outline of the methodology employed in this study 
follows: 

1. The quantity and quality of world mercury resources 
were evaluated in relation to physical, technological, and 
other factors that affect production for each of the deposits 



Identification 

and 

selection 

of deposits 



Tonnage 

and grade 

determination 



Engineering 
and cost 
evaluation 



Deposit 

report 

preparation 



Mineral 

Industries 

Location 

System 

(MILS) 

data 



MAP 

computer 

data 

base 



Taxes, 

royalties, 

cost indexes, 

prices, etc ... 



MAP 

permanent 

deposit 

files 



Data 

selection and 

validation 



Economic 
analysis 



Data 



Availability 
curves 



Analytical 
reports 



Variable and 

parameter 

adjustments 



Sensitivity 
analysis 



Data 



~ Availability 
curves 



Analytical 
reports 



Figure 6.— Flowsheet of evaluation procedure. 



evaluated. Only primary mercury sources containing at 
least 600 flasks of mercury were considered. 

2. Capital and operating costs for approprate mining, 
concentrating, and processing methods were estimated for 
each deposit. 

3. An economic analysis was performed for each deposit 
to determine the total unit production cost. 

4. Individual deposit cost-production relationships were 
aggregated and presented as total and annual availability 
curves to show production potentials at various production 
costs. 

5. Sensitivity analyses on the effect of inflation, energy, 
and labor costs were also perfomed. 

After a deposit was selected for analysis, a comprehen- 
sive evaluation of the property was performed. Domestic 
properties were evaluated by personnel at the Bureau's 
Field Operations Centers in Denver, CO, and Spokane, WA. 
Foreign properties were evaluated by personnel of the 
Minerals Availability Field Office in Denver, CO, from data 
collected by contractors. The designed mining and milling 
capacities were used for producing properties. For deposits 
not in production, mining, concentrating, smelting, refin- 
ing, and transportation methods and production parameters 
were chosen based on applicable engineering principles, 
available deposit data, and current technology. 

When possible, actual company cost data were used. If 
these data were not available, capital and operating costs 
were estimated. A costing system developed for the Bureau 
(2) was used for some domestic deposits. Use of this costing 
system produces estimates that historically have fallen 
within 25 pet of actual costs. 

Capital expenditures were estimated for exploration, 
development, and mine and mill plant and equipment which 
include costs for mobile and stationary equipment, construc- 
tion, engineering, support facilities and utilities (infrastruc- 
ture), and working capital. Infrastructure includes all 
necessary costs for access roads, water facilities, power 
supply, port facilities, and personnel accommodations. 
Working capital is a revolving cash fund for operating ex- 
penses such as labor, supplies, taxes, and insurance. A work- 
ing capital based on 2 months or 60 days of operating cost 
was used in evaluations. 

All capital investments incurred prior to 15 yr of the 
study date (January 1984) were assumed to be fully 



depreciated or written off. Capital costs incurred less than 
15 yr before 1984 were reported in dollar values of the year 
incurred; however, these costs were adjusted to reflect the 
remaining book value of the investment as of January 1984. 
All capital investments subsequent to January 1984 were 
reported in constant January 1984 dollars. 

Mine and mill operating costs were developed for each 
deposit. The total operating cost is the sum of the direct and 
indirect costs. Direct operating costs include production and 
maintenance labor, materials, payroll overhead, and 
utilities. Indirect operating costs include administrative 
costs, facilities maintenance and supplies, and research and 
development. Costs not included in operating costs but used 
in the analyses include fixed charges, including transpor- 
tation costs, taxes, insurance, depreciation, deferred ex- 
penses, and royalties. 

After capital and operating costs were determined, data 
were entered into the Supply Analysis Model (SAM) (4). The 
Bureau developed SAM to perform an economic analysis 
which either presents the results as the primary commod- 
ity price (total production cost) needed to provide a 
stipulated rate of return or, for a given price, generates a 
rate of return on investment. The rate of return used in this 
study is the discounted cash flow rate of return (DCFROR), 
most commonly defined as the rate of return that makes 
the present worth of cash flows from an investment equal 
to the present worth of all aftertax investment. For this 
study, a 15-pct rate of return was considered necessary to 
cover the opportunity cost of capital plus risk. For some 
Government-owned operations, rate of return (profit) may 
not be required for continued production. However, for com- 
parison purposes, each deposit was analyzed at a 15-pct rate 
of return. 

Detailed cash-flow analyses were generated for each 
deposit under consideration. After each deposit's total cost 
of production was determined, individual deposit tonnages 
were aggregated at increasing production costs to determine 
mercury availability from all deposits evaluated. The 
results of these analyses are presented as availability curves 
discussed later in this report. 

Sensitivity analyses were performed to determine the 
effects of inflation and increasing labor and energy costs 
on the availability of mercury. Separate analyses were made 
for producing and nonproducing properties. 



GEOLOGY 



Traces of mercury can be found in most natural 
substances. Mercury is recovered primarily as the red 
sulfide mineral cinnabar (HgS). Native mercury metal, 
metacinnabar, livingstonite, corderoite, and other mercury 
minerals are present in some ores but rarely in sufficient 
quantity to be recoverable. Principal gangue minerals in- 
clude silica, feldspar, and carbonate minerals, with pyrite, 
marcasite, serpentine, and stibnite present in some 
localities. Valuable metals such as gold and silver are 
generally present only in trace amounts, although mercury 
has been recovered as a byproduct of gold and silver min- 
ing. All major producing districts recover mercury with no 
significant byproducts. 

Mercury can be found in a wide variety of host rocks. 
Common host rocks include limestone, calcareous shale, 
sandstone, serpentine, chert, andesite, basalt, and rhyolite. 



Significant mercury deposits are found chiefly in regions 
of extensive Tertiary or Quarternary volcanic and tectonic 
activity in areas with a high degree of faulting or fractur- 
ing. Deposits are classed as epithermal, formed by the 
deposition of ore minerals from aqueous solutions at 
relatively low temperatures and shallow depths (5). The 
bulk of mercury ore mined has been from depths less than 
300 m, although a maximum mining depth of 730 m has 
been achieved in California. For most deposits, the highest 
grade of ore is generally found in ore-bearing levels closest 
to the surface. Ore has been concentrated by replacement, 
open-space filling, and detrital concentration (1). 

Mercury ore bodies are commonly small, irregular, and 
erratic (5). Three common forms are distinct veins of very 
high-grade cinnabar, disseminated ore occurring in fine- 
grained or brecciated ore zones, or disseminated ore along 



highly fractured contact zones. Higher grade disseminated 
ore is usually associated with open-textured rock types such 
as sandstone or coarse breccia (6\ Lateral extent of ore zones 
is highly variable; generally, individual ore zone dimensions 
do not exceed 100 m. Vein thickness ranges from less than 
1 to 21 m. The following brief descriptions of some principal 
deposits illustrate the diversity of occurrence that 
characterizes mercury deposits. 

The Almaden district of Spain, historically the greatest 
producer of mercury, illustrates ore that occurs in highly 
concentrated bodies distinct from the surrounding host rock. 
The Mina Antigua ore occurs within three distinct quart- 
zite veins enclosed in folded, faulted metasedimentary rocks 
of Silurian-Devonian age. El Entredicho ore consists of two 
distinct high-grade quartzite veins separated by a zone of 
carboniferous quartzite containing disseminated cinnabar. 
Ore in the Las Cuevas area of Almaden occurs as replace- 
ment of volcanics. rather than quartzite. 

The Abbadia S. Salvatore Mine of the Monte Amiata 
district in Italy is an example of ore that has been 
disseminated throughout fine-grained or highly brecciated 
rock. Detrital cinnabar has been concentrated in highly frac- 
tured solution caves of Eocene limestone and shale. 
Dissemination of ore depends upon the extent of fractur- 



ing of the ore zones; consequently, mineralization and ore 
grade are erratic and variable. 

Another type of disseminated ore is exemplified by the 
Turkish mercury deposits. Ore at the Halikoy Mine occurs 
in a highly fractured contact zone between mica schist and 
granitic gneiss. In the Konya area, ore occurs along a 
limestone-phyllite contact in areas where the host rocks 
have been folded and fractured. Cinnabar is erratically 
distributed as disseminations, clusters, and discontinuous 
veinlets. 

In the Opalite district of Nevada, the location of the 
McDermitt Mine, ore occurs as lenses and irregular beds 
within argillized tuffaceous Miocene lakebeds and brec- 
ciated areas of the silicified lakebed sediments within 
45 m of the surface (6). Unlike other deposits, ore occurs 
as both cinnabar and the mineral corderoite (Hg 3 S 2 Cl 2 ). The 
corderoite decreases in quantity with depth. 

Mercury deposits in California have traditionally pro- 
duced significant quantities of mercury, but are no longer 
producing. In this region, ore occcurs in silica-carbonate rock 
derived from hydrothermally altered serpentine (5). Cin- 
nabar is found where the silica-carbonate has been replaced 
along steep fracture zones extending to depths up to 730 m. 



RESOURCES 



Demonstrated resources for 15 deposits evaluated in this 
study have been estimated at 25 million mt of in situ ore 
at a weighted average grade of 0.74 pet Hg. This ore con- 
tains an estimated 5.3 million flasks of mercury, of which 
4.6 million flasks, or 87 pet, is recoverable utilizing current 
technology. Table 3 gives the demonstrated mercury 
resources as of January 1984 for evaluated market economy 
countries. Because of the sensitivity of mercury resource 
information in some countries, detailed information for in- 
dividual deposits could not be reported. 

Mercury is currently being recovered in a limited number 
of areas around the world. Approximately 57 pet of the total 
recoverable mercury at the demonstrated level is derived 
from six deposits that were producing at the time of this 
study. Much of the mercury currently being recovered is 
produced from the Almaden district in Spain. In 1983, Spain 
produced 43 pet of the total mercury for market economy 
countries, or 23 pet of the world's total mercury (12). Other 
currently producing market economy countries that are in- 
cluded in this study are Algeria, Turkey, and the United 
States. 

Demonstrated resources from nonproducing deposits 
make up 43 pet of the total recoverable resource available 



from market economy countries. Much of the mercury 
resource recoverable from nonproducing deposits occurs in 
Italy; remaining resource material is available from 
Canada, the Philippines, Turkey, and the United States. 
Italian deposits of the Monte Amiata district are the source 
for 38 pet of the total recoverable mercury from market 
economy countries and have the potential for supplying 89 
pet of the recoverable mercury from market economy coun- 
tries not currently producing. 

While this study evaluates demonstrated resources of 
known areas, additional mercury potential exists in areas 
with resource potential currently at the identified level. As 
these occurrences are further explored and resources 
upgraded to the demonstrated level, the quantity of 
available mercury could be increased. Approximately 17 
million flasks of world mercury are reported to exist at the 
identified level (12). 



DOMESTIC RESOURCES 

Only 4 pet of the total demonstrated mercury resources 
can be recovered from domestic deposits. The United States 



Table 3.— Demonstrated mercury resources as of January 1984 

Number ln si,u Hg, 10 3 flasks 

of Hg grade. Ore, Con- 

Country deposits pet 10 3 mt tained 

ice- 5 2 1.00 356 103.5 

Itary 2 56 12,248 2,006.9 

Turkey 4 .33 2,053 195.3 

United States 4 27 2,520 199.9 

Ottwr 3 1_29 . 7,410 2,766.5 

Total or average 2 15 !74 24,587 5,272.1 

Produced 6 1.34 7,703 3,005.4 

NonOfOducers 9 .46 16,884 2,266.7 

'Other includes Canada. Philippines, and Spain Owing to proprietary considerations, these countries could not be treated separately. 
'Computations using tabulated numbers may vary from reported values, owing to individual rounding. 



Recover- 
able 



94.3 

1,752.2 

158.3 

161.4 

2,401.8 



4,568.0 
2,608.0 
1,960.0 



10 



produced only 13 pet of the world's primary mercury in 1983 
(24 pet from market economy countries) (12). Domestic ore 
is of a much lower grade than ore produced throughout the 
world. While the weighted average ore grade for all market 
economy countries is 0.74 pet Hg, domestic ores have a 
weighted average grade of 0.27 pet Hg. The estimated ore 
grade of domestic producers is approximately one-third the 
grade for all world producers included in this study. 

The number of producing domestic mercury operations 
has decreased dramatically in recent years. There were 109 
active mercury mines in 1969, 24 in 1973, and only 1 in 
1984 (6, 12). The bulk of domestic mercury production comes 
from the McDermitt facility in northern Nevada; a small 
amount of mercury is recovered from the Carlin and Pin- 
son Mines in Nevada as a byproduct of gold refining. At 
present, mercury produced from secondary sources makes 
up 36 pet of total domestic mercury production (12). 

Demonstrated resources at the McDermitt operation, 1.1 
million mt at 0.438 pet Hg (10), constitute 44 pet of the total 
domestic resource tonnage. The deposit, however, contains 
approximately 74 pet of the current total recoverable mer- 
cury from domestic sources. The ore grade is significantly 
higher and ore occurs at a much shallower depth than in 
most other domestic deposits; consequently, it is not sur- 
prising that this deposit can sustain production while 
economic conditions prohibit production from other domestic 
deposits. 

Regions with significant demonstrated resource poten- 
tial include California, Nevada, and Texas. Traditionally, 
the California deposits were major producers. With the 
discovery of the McDermitt deposit in the 1970's and chang- 
ing economic conditions, Nevada has recently surpassed 
California in mercury potential. Figure 7 gives the mercury 
resource distribution by State. Areas of significant mercury 
potential that merit investigation to further delineate 
resources are listed in appendix B. 

Mercury in California occurs along the Coast Range in 
a southeast-trending belt extending up to 650 km long and 
120 km wide (11). The higher grade areas have been mined 
extensively; consequently, remaining resources tend to be 
widely disseminated and low grade. The Gibraltar deposit 
in Santa Barbara County is the only California deposit con- 
sidered to have substantial resources at the demonstrated 
level. 




Figure 7.— Distribution of demonstrated domestic mercury 
resources. 



The principal mercury-bearing areas in Nevada occur 
along a northerly trending belt in sedimentary and volcanic 
rocks in the west-central part of the State, extending south 
from McDermitt roughly 350 miles (11). Higher grade oc- 
currences are found in the northern part of the belt. The 
B&B Mine is typical in that the low-grade ore is contained 
within highly disseminated, faulted volcanics of Tertiary 
age. 

Mercury has been found in marine sediments of 
southwestern Texas. The region consists of numerous small 
occurrences and districts; mercury mining in the region 
ceased in 1960. The Study Butte Mine is the only remain- 
ing deposit with documented resources at the demonstrated 
level. Ore in this region is found at a greater depth than 
in Nevada and most California mines and would require 
underground mining methods. 

The sustained low mercury price and demand in recent 
years have not encouraged new domestic mercury explora- 
tion. Most of the exploration took place in the 1950's when 
production was widespread and Government funding was 
available. Areas with significant identified resource poten- 
tial have been found in Alaska, Arizona, California, Idaho, 
Nevada, Oregon, and Texas. Although most of the past pro- 
duction has occurred in California and Nevada, the areas 
of greatest future potential resources are likely to be Alaska, 
California, and Nevada, in areas where exploration has 
been limited. The Bureau estimates that approximately 
490,000 flasks of contained mercury are available in the 
United States at the identified level (2). 

Significant mercury is also available from other 
domestic sources. At the end of 1983, the National Defense 
Stockpile contained 178,315 flasks of primary mercury, 
reported industry stocks amounted to 31,518 flasks of 
primary mercury, and 35,305 flasks of secondary mercury 
are reportedly held in a Department of Energy stockpile 
(2). Since these sources of supply are not generally available 
on world markets, they were not included in the availability 
study; however, their importance should be noted in the 
overall domestic supply picture. 



FOREIGN RESOURCES 

Foreign mercury resource potential is limited to a few 
regions. Except for Mexico, where mercury resources con- 
sist of numerous small deposits, potential mercury resources 
are restricted to well-defined districts in Algeria, Canada, 
China, Italy, the Philippines, Spain, Turkey, the U.S.S.R., 
and Yugoslavia. Discussions in this study are limited to 
market economy countries whose resources are given in 
table 3. 

The Almaden district in Spain has ore zones which are 
generally much larger, less irregular, and higher grade, as 
much as 20 pet Hg in some areas, than other districts. On 
an average basis, ore at Almaden is approximately 35 pet 
higher grade than the next higher grade deposit and 600 
pet higher grade than an average U.S. mercury deposit. Ap- 
proximately half of the total recoverable mercury available 
from market economy countries comes from the Almaden 
district. It is anticipated that the Almaden operation could 
continue to operate at current production levels for at least 
the next 100 yr should inferred resources of this deposit be 
proven, although production at much deeper levels may 
allow for a much greater mine life (7). 

The Monte Amiata district in Italy has the second 
largest resource potential for market economy countries. 



11 



The district contains over 12 million mt of ore averaging 
0.56 pet Hg. 38 pet of the recoverable mercury from market 
economy countries. All production in the district ceased in 
1982 for economic reasons. Together. Spain and Italy make 
up the bulk of recoverable mercury for the evaluated market 
economy countries. 

The mercury reserve potential of Turkey is similar to 
that of the United States. Ore occurs in several districts 
distributed across western Turkey, each district differing 
in host rock and mode of occurrence. Demonstrated 
resources for Turkey are 2.1 million mt of ore at 0.33 pet 
Hg. or roughly 3 pet of the evaluated resources based on 
recoverable mercury. 

Canadian mercury potential is centered along the Pin- 
chi fault zone in central British Columbia. The region con- 
tains over 1.2 million mt of demonstrated mercury ore at 
0.29 pet Hg. Mining in the region first occurred during 
World War EI: the Pinchi Lake facility operated briefly from 
1968 to 1975. 

Algerian mercury deposits have achieved a greater 
degree of importance as a result of recent discoveries and 
cessation of production from other deposits in recent years. 
Demonstrated resources are 356.000 mt at a relatively high 
average grade of 1.0 pet Hg. Although Algeria contains 2 
pet of the total recoverable mercury resources of market 
economy countries, it supplied 11 pet of the total produc- 
tion from these countries in 1983 (12). 

The ore grade from Philippine mercury deposits is 
marginal, and unless substantial mercury is discovered, it 
is unlikely that mercury from the Philippines will seriously 
influence mercury markets. 

Little information is available about mercury resources 
in South America. Peru once produced substantial amounts 
of mercury from the Santa Barbara Mine, but since its ex- 
haustion, little mercury has been recovered from the sur- 
rounding area. Other South or Central American countries 
that have had minor production include Honduras, Colom- 
bia, Chile, and Venezuela. Total demonstrated resource 
potential from South American mercury deposits could 
amount to 30,000 flasks (2), but this amount could change 
should more exploration prove out additional mercury-rich 



areas. The resource figures for this region have not been 
included in this study because of their speculative nature. 

Mercury resource potential from Mexico is reported to 
amount to 250,000 flasks {12), although as much as 1 million 
flasks of low-grade mercury may be available at costs ex- 
ceeding $600 per flask. Mexican deposits are generally 
small, erratic, and highly variable in mode of occurrence 
and geologic association. Mexican statistics show minor 
mercury production since 1978. Currently Mexico is pro- 
ducing mercury as a byproduct or recovering it from small 
operations. All of the larger mercury operations have been 
dismantled. Because of the nature of the ore, individual 
Mexican deposits did not meet the deposit standards 
established for this evaluation, so were not included in this 
study. Reliable resource data are scarce, and most operating 
properties produce on a haphazard schedule based on 
market demand. Mexican mercury operations have re- 
sponded rapidly to significant demand and price fluctua- 
tion in the past, so could possibly expand production if de- 
mand warranted such action. 

Mercury resource potential from Yugoslavia is reported 
to amount to 500,000 flasks (2). Since available data are 
scarce, and confirmation of detailed economic data is not 
possible, resources from Yugoslavia have not been included 
in economic evaluations. t 

Several other areas have produced mercury as a 
byproduct from base metal refining. Approximately 5 pet 
of world mercury production in 1979 came from base metal 
refining operations in Australia, Czechoslovakia, Finland, 
and the Federal Republic of Germany (6); this potential 
resource has not been included in economic evaluations 
since the study is limited to primary resources. 

Mercury production from centrally planned economy 
countries has recently become increasingly influential on 
world markets. In 1982, production occurred from mines in 
the U.S.S.R., China, and Czechoslovakia. While these 
resources are not included in the economic evaluations of 
this study, it should be noted that 46 pet of present produc- 
tion and 23 pet of estimated world resources originate from 
centrally planned economy countries (12). 



EXTRACTION TECHNOLOGY 



MINING 

Mercury ore is mined by both surface (37 pet) and 
underground '63 pet) methods. The mode of occurrence of 
the mercury deposit determines the mining methods. The 
bulk of mercury ore is currently mined by conventional open 
pit mining methods. The ore and overburden are separate- 
ly drilled, blasted, loaded, and hauled. Drilling is ac- 
complished using track drills, equipped to bore holes 8.89 
to 10.16 cm in diameter. ANFO is generally used as a 
blasting agent with a powder factor which could range from 
0.1 to 2.4 kg of explosive per ton of material blasted. Broken 
ore is loaded by shovels and front-end loaders and is haul- 
ed by truck and rail to the beneficiation plant or to an on- 
site crusher. 

The McDermitt Mine in Nevada is the only producing 
domestic mercury mine. It is presently the largest surface 
mercury mine in the market economy countries. Mining at 
McDermitt is relatively easy and somewhat atypical of the 
mercury industry. Blasting is required only in the highly 



siliceous opalite rock which underlies the mercury ore. The 
ore, a relatively unconsolidated mixture of lacustrine 
sediments and volcanic tuffs, is mined by scrapers. 

Various underground mining methods are currently be- 
ing conducted by the mercury industry; however, narrow- 
vein mining methods predominate, with cut-and-ill mining 
the most commonly used. Vertical crater retreat (VCR) min- 
ing, a relatively new mining method that has proven much 
more economical than cut-and-fill, is gradually becoming 
the primary method. 

All underground mercury mines utilize conventional 
drilling, blasting, loading, and hauling. Drilling is done by 
jumbo drills in the larger mines and by handheld jackleg 
drills in the smaller. Mines employing the VCR method use 
down-hole drills. For the most part, ANFO is the blasting 
agent; powder factors could range from 0.2 to 0.5 kg of 
blasting agent per ton of ore. Broken ore is then loaded by 
mucking machines, slushers, or manually, and hauled by 
various means out of the mine. 

The Antigua Mine, part of the Almaden operations of 



12 



Spain, is presently the largest underground mine in the 
market economy countries. The VCR mining method is 
replacing cut-and-fill methods at this operation. 



BENEFICIATION 

In general, beneficiation of mercury ore begins with 
crushing and screening. Mercury -bearing ore crushes more 
readily than barren rock; therefore, a crude separation of 
ore and barren rock is conducted by screening. Primary 
crushing is done by jaw crushers; screening, by grizzlies. 
In recent years, this first step in the beneficiation process 
has moved from the beneficiation facility to the mine site. 
A typical flowsheet for the mercury beneficiation process 
is shown in figure 8. Efficient mercury recovery can exceed 
95 pet. 

Secondary crushing and screening is accomplished by 
gyratory cone crushers and scalping screens. Ore is reduced 
in size from 7.62 cm to minus 1.91 cm. This final size has 
been found to be optimal for the subsequent roasting step. 

In some operations mercury ore is further upgraded 
before roasting. Under these circumstances, ore is further 
reduced in size by use of rod mills, ball mills, or 
semiautogenous mills. Ore is then concentrated by flota- 
tion, jigging, and tabling. Flotation has been proven to be 
the most successful concentrating method, producing con- 
centrates from 25 to 75 pet and recovering almost 90 pet 
of the mercury. This upgrading process has resulted in im- 
proved efficiency and considerable energy savings in the 
subsequent roasting step. 

Roasting is essentially a distillation process and con- 
sists of heating the concentrate followed by condensation 
of the mercury vapor. Either mechanical furnaces or retorts 
are used in roasting. Mechanical furnaces include both 
multiple-hearth furnaces and rotary furnaces. Concentrate 
is fed continuously in furnaces; and temperature for volatiz- 



Raw ore 



Screening 




ii 




Crushing 






* 








Grinding 






1 
1 
* 


'i 




Flotation 


Roasting 


«■ 


1 
_j 


" 




Bottling 





Market 

Figure 8.— Flowsheet of typical mercury beneficiation process. 

ing is set at 746° C. Both types of furnaces exhibit advan- 
tages and disadvantages; the multiple hearth is more 
capital intensive than the rotary but much more energy 
efficient. 

Gases from furnacing are passed through dust collec- 
tors. Dust is collected and further processed, and the dust- 
free gas is directed to the condenser system, where mercury 
vapor is condensed and collected. The condenser system con- 
sists of a series of cast iron or stainless steel pipes; mer- 
cury is collected at the bottom of pipes in launders or 
buckets. 

Retorts are also used in roasting mercury ore. They are 
relatively inexpensive compared to the mechanized roasters 
but exhibit several disadvantages: mercury ore must be 
batch loaded, manually charged, and discharged. In addi- 
tion, they are relatively small in capacity. 



ENVIRONMENTAL CONSIDERATIONS 



While mercury ores and to a large extent metallic mer- 
cury are not particularly toxic to plants and animals, mer- 
cury vapor and many of its compounds are poisonous to all 
forms of life. Therefore, care must be taken to avoid con- 
tamination of the environment when mining and process- 
ing mercury ore, and stringent precautions must be under- 
taken to avoid the poisoning of personnel affiliated with the 
mercury operation. 

Mercury poisoning, mercurialism, begins with the ab- 
sorption, ingestion, or inhalation of large quantities of mer- 
cury vapor over a short period of time (acute poisoning) or 
smaller quantities of mercury vapor over longer periods 
(chronic poisoning). Symptoms of acute poisoning include 
metallic taste, abdominal pain, vomiting, headaches, diar- 
rhea, and cardial weakness. Chronic poisoning develops 
gradually and often without conspicuous warning signs. 
Early symptoms may include general weakness, inflamma- 
tion of the mouth, loosening of the teeth, excessive saliva- 
tion, emotional instability, and body tremors. 

Personnel associated with mercury operations process- 
ing toxic mercury compounds are most often the victim of 
chronic mercury poisoning. Many years ago, prisoners and 
slaves were used to mine and process mercury ore, with lit- 
tle regard to their health. Today, worker safety is a prime 
consideration. Mercury vapor emissions from the process- 



ing furnaces or retorts have been radically reduced. 
Educating workers regarding mercury poisoning and its 
causes has had a profound positive impact. Direct exposure 
to high concentrations of mercury vapor is avoided. Safety 
gear, such as helmets, respirators, gloves, and rubber boots, 
is worn; the importance of hygiene is accented. Regularly 
scheduled physical examinations are required. 

Domestic mercury workers are protected by Mine Safety 
and Health Administration and Occupational Safety and 
Health Administration regulations. MSHA regulations 
limit mercury exposure to a maximum concentration of 
50 piglm* or 1 mg/10 m 3 in an average 8-h period (6). The 
Bureau has been active in research to improve the health 
and safety of mercury workers. The Environmental Pro- 
tection Agency has issued regulations on the discharge of 
mill waste water from the ore and milling facilities under 
the Clean Water Act, December 3, 1982. Effluent limi- 
tations under this act are set at 0.002 mg/L for any given 
day and at 0.001 mg/L as an average daily value for 30 
consecutive days. 

Foreign environmental regulations are generally less 
stringent than domestic regulations. However, a unique 
rule is applied to mining and processing at the Almaden 
operations in Spain, where employees are scheduled to work 
only two or three 6-h shifts per week. 



13 



CAPITAL AND OPERATING COSTS 



Capital and operating costs in this study have been 
developed based on actual data or estimated from best 
available sources. The average total production cost 
estimated for each deposit analyzed includes mining and 
concentrating costs, transportation costs to the processing 
facilities, capital recovery, taxes, and profit. These costs 
often vary greatly depending on such factors as size of opera- 
tion, mining method, deposit location, stripping ratio, depth 
of ore body, grade of ore, processing losses, energy and labor 
costs, environmental regulations, and tax structure. 

Capital costs presented in this section reflect nonproduc- 
ing operations only. These costs reflect either the cost re- 
quired to develop the operation, construct all facilities, and 
begin production or. as in most cases, the additional capital 
required to recondition preexisting facilities and construct 
any additional facilities to enable the mine to resume 
operations. 

Operating costs are weighted averages reported in terms 
of cost per recoverable ton of ore and cost per flask of 
recoverable mercury over the future life of the operation. 



CAPITAL COSTS 

Capital costs include costs for exploration, development, 
mine and mill plant and equipment, working capital, and 
infrastructure, where required. Relatively simple process- 
ing steps are required to obtain prime virgin mercury. Any 
smelting and or refining operations that may be required 
have either been incorporated into the mill capital cost or 
been treated as a mill custom charge included in the mill 
operating cost. 

Most deposits included in this study either are currently 
producing or have produced within the past 10 yr. Many 
nonproducing operations considered in this study have ex- 
isting facilities that only need to be rehabilitated or mod- 
ernized in order to resume production. Capital costs for 
these operations include all costs necessary to rehabilitate 
the facilities to enable production to begin utilizing current 
mining and beneficiation practices. Capital costs for pro- 
ducing operations are not included because most have been 
operating for many years and a large portion of the initial 
investment has been depreciated. Capital expenses for these 
operations are limited to replacement or expansion of 
facilities. 

Analyses indicate that capital costs required to bring 
the principal nonproducing mercury deposits back into pro- 
duction range from $900,000 to $10.5 million, or from $15 
to $140 per metric ton of ore mined. Larger deposits require 
larger capital expenditures but were lower cost operations 
on a per ton basis. 

Modernization capital costs vary considerably from 
country to country. Capital costs in the United States range 
from about $2,900,000 for small operations to $10,500,000 
for larger operations. U.S. costs were the highest on a cost 
per ton basis, ranging from $40 to $140 per metric ton of 
ore mined on an annual basis. Costs of rehabilitating 
Turkish mines were also high on a cost per ton of ore basis. 
Costs ranging from $900,000 to $2.3 million were required 
for small operations producing 15,000 to 50,000 mt of ore 
annually. Capital costs in Canada and Italy of $20 to $40 
per metric ton of ore are comparable, but modernization 
costs for the higher production ^340,000 to 350,000 mt) 
Canadian operation are $7.6 million to $8.4 million, while 



smaller (20,000 to 230,000 mt) Italian properties have 
capital costs ranging from $1 million to $5.4 million. 
Medium-size operations in the Philippines have the lowest 
capital cost on a per ton of ore basis ($15 to $20). Total costs 
range from $2.8 million to $3.2 million. 

Mine capital costs range from 44 to 93 pet of the total 
capital cost. The highest mine costs were found for mercury 
deposits in Canada, the United States, and Italy, where the 
underground mining methods to be employed are very 
capital intensive. 

Mill capital costs range from 7 to 56 pet of the total 
capital cost. Mill costs are low because many of the deposits 
under consideration have existing processing facilities re- 
quiring only minor modifications to bring the facility back 
on-line. 



OPERATING COSTS 

Summaries of estimated operating costs for principal 
mercury deposits are given in table 4 in terms of cost per 
recoverable ton of ore and in table 5 in terms of cost per 
recoverable flask. For each producing or nonproducing coun- 
try considered in this study, a range of costs is given for 
each operating cost category. Individual deposit costs, while 
included within the reported cost ranges, are withheld to 
preserve proprietary data. 

Operating costs include the costs of mining, beneficia- 
tion, and all transportation up to the last stage of process- 
ing prior to market. Any smelting or refining, if required, 
has been included in the mill operating cost. Mine and mill 
operating costs include all costs for labor, energy, and sup- 
plies, and indirect costs of administration, maintenance, 
overhead, etc. All other miscellaneous costs have been in- 
cluded in the "other" category. This includes recovery of 
capital, 15-pct return on investment, taxes (property, 
severance, State, and Federal), and any additional transpor- 
tation charges (where applicable). No byproduct revenues 
have been included in this analysis, since mining operations 
commonly produce mercury as a single marketable com- 
modity without any byproducts. Total cost reflects the sum 
of the mine, mill, and other categories and can be compared 
to a long-term market price which indicates which proper- 
ties have sufficient return on capital investment to provide 
an incentive to produce. If an operation showed costs that 
consistently were higher than the market price, the com- 
pany might consider a temporary cessation of operations 
until market conditions improve. State owned or controlled 
operations may continue producing even under a non- 
profitable situation if the resulting losses are less than those 
incurred if the operations were closed. A closure may re- 
quire payment of unemployment, welfare, or loss of train- 
ing benefits. Governments may also need sales revenues 
generated by the operation to import other needed materials 
into the country. 

Mining costs on a per ton of ore basis vary from 10 to 
75 pet of the total operating cost for evaluated mercury 
deposits. The highest mining costs occur for the Italian mer- 
cury deposits where ore is recovered by expensive 
underground methods; the lowest costs occur in surface min- 
ing operations in the United States and Turkey, where min- 
ing occurs at shallow depths and requires minimal blasting. 
For those deposits studied, mining costs average 25 pet of 
the total operating cost for surface mines and 46 pet for 



14 



Table 4.— Estimated operating costs for principal mercury deposits, per metric ton of ore 

Status Type Annual Cost range (January 1984 $) 2 

and of production rate, 

location mining' 10 3 mt Mine Mill Other 3 Total 

Producer: 

United States S 250-300 $5 - $10 $5 - $10 $5 - $10 $20 - $30 

Turkey U 40-50 20-30 10-20 1- 10 40- 50 

Spain S-U 150-200 10- 20 30- 40 10- 20 50- 60 

Algeria S 20-40 20- 40 30-40 10-30 80- 90 

Weighted average — 94 14 18 11 43 

Nonproducer: 

Philippines S 160-170 5-10 10-20 5-10 20-30 

Turkey S-U 15-50 1-20 10- 20 10- 40 20- 70 

Canada S-U 340-350 10-20 5-10 10- 20 30- 40 

United States S-U 20-130 5-60 5- 40 10- 70 30-170 

Italy U 20-230 40-60 10-20 5- 20 70- 80 

Weighted average — 118 25 12 14 5T 

'S = surface; U = underground. 

2 Estimated costs fall within the given range; range limits may not reflect specific actual costs. 

3 "Other" cost category includes costs for capital recovery, taxes, and profit to achieve a 15-pct DCFROR. 

Table 5.— Estimated operating costs for principal mercury deposits, per flask of recoverable mercury 

Status Type Annual Cost range (January 1984 $)* 

and of production rate, 

location mining 1 10 3 mt Mine Mill Other 3 Total 

Producer: 

United States S 250-300 $80 - $90 $80 - $90 $70 - $80 $240 - $250 

Turkey U 40-50 230-280 160 - 190 40 - 60 430 - 520 

Spain S-U 150-200 20- 30 60- 70 30- 40 120- 130 

Algeria S 20- 40 80-220 90- 250 70- 150 240- 600 

Weighted average — 94 97 99 62 258 

Nonproducer: 

Philippines S 160-170 230-250 460 - 470 410 - 420 1,100 - 1,200 

Turkey S-U 15-50 150-230 220 - 370 450 - 480 900-1 ,000 

Canada S-U 340-350 270-280 1 10 - 120 170 - 180 500 - 600 

United States S-U 20-130 360-570 200-1 ,570 330 - 2,700 900 - 4,700 

Italy U 20-230 200-450 60- 100 50- 60 300- 600 

Weighted average — 118 329 309 419 1,057 

1 S = surface; U = underground. 

2 Actual costs fall within the given range; range limits may not reflect specific actual costs. 

3 "Other" cost category includes costs for capital recovery, taxes, and profit to achieve a 1 5-pct DCFROR. 



underground mines. The average mining cost is $14 per 
metric ton of ore for surface operations and $31 per metric 
ton of ore for underground operations. 

Milling costs on a per ton ore basis range from 16 to 
53 pet of the total operating cost for mercury deposits con- 
sidered in this study. Generally, beneficiation techniques 
are similar for all operations considered; this can be seen 
from the relatively low degree of variability of milling costs 
(in comparison to mining costs). The highest milling costs 
occur for Algerian deposits which operate at a compara- 
tively low production rate; low milling costs are found in 
deposits with much higher production rates such as the ma- 
jor deposits in the United States, Canada, and Italy. The 
average milling cost is $19 per metric ton of ore for the mer- 
cury deposits evaluated in this study. 

The total operating cost for producing mines ranges from 
$20 to $30 per metric ton of ore in the United States to $80 
to $90 per metric ton of ore for Algerian mercury operations 
(table 4). The average total operating cost for a producing 
mine is $57 per metric ton of ore. On a cost per flask of prod- 
uct basis, operating costs for producing mines range from 
$120 to $130 per flask in Spain to $240 to $600 in Algeria 
(table 5). The average total operating cost for a producing 
deposit is $360 per flask of mercury. While the U.S. mer- 
cury deposit has the lowest operating cost range on a per 
ton basis, it does not have the lowest cost when measured 



per flask of recoverable mercury (table 5), which is in- 
fluenced by the grade of the mercury ore. On a cost per ton 
of product (flasks of recoverable mercury) basis, the high- 
grade Spanish ores have the lowest total operating cost 
when compared to the lower grade ores of the United States, 
which have higher operating costs. Algerian deposits ap- 
pear to have the highest operating costs owing to a com- 
bination of low production rate, lower grade, and higher 
energy and labor costs, but costs vary widely due primarily 
to the large grade variation of Algerian deposits. 

The total operating cost for nonproducing deposits 
ranges from about $20 per metric ton of ore for deposits in 
the Philippines to as much as $170 per metric ton for some 
U.S. deposits. The average total production cost estimated 
for a nonproducing deposit is $65 per metric ton of ore, or 
$1,296 per flask of mercury. A much wider cost range ex- 
ists for nonproducing deposits on a cost per flask of mer- 
cury basis. Italian mercury deposits have costs ranging from 
$300 to $600 per flask, while very low-grade mercury 
deposits in the United States have costs that reach $4,700 
per flask. At a January 1984 mercury price of 
approximately $300 per flask, it is apparent that a much 
higher mercury price will be required before many of these 
nonproducing operations could become profitable using ex- 
isting technology. 



15 



MERCURY AVAILABILITY 



The potentially recoverable mercury from market 
economy countries is illustrated by availability curves and 
tables. Of the 15 properties analyzed in this study, one prop- 
erty containing approximately 6,000 flasks of mercury has 
been excluded because of unusually high costs of produc- 
tion. After cost and quantity data were determined for each 
property, total and annual availability curves were con- 
structed to indicate recoverable resource availability. These 
analyses are based on the following assumptions: 

1. No definite startup dates were known for nonproduc- 
ing deposits; preproduction development work for each 
deposit was proposed to begin in year "N" 

2. Time lags related to permitting, environmental im- 
pact statements, and other possible delays affecting produc- 
tion are minimized. 

3. Each operation will produce at its full design 
capacity. 

4. Competition and demand conditions are such that 
each operation will be able to sell all of its output at its an- 
ticipated total production cost. 

5. Total cost, also called commodity or incentive price, 
is defined as the average total cost of production for the com- 
modity and covers all production costs including a 15-pct 
rate of return on invested capital. 

6. Current tax structures and 100-pct equity were used 
in all simulations. 



TOTAL AVAILABILITY 

Table 6 reports the total availability of mercury from 
evaluated deposits in market economy countries. The 
January 1984 market price for prime virgin mercury at New 
York was approximately $300. At a total production cost 
equivalent to this price, approximately 2.5 million flasks 
of mercury are available, all from currently producing 
deposits. When the total production cost rises from $300 to 
$600 per flask, the amount of mercury available increases 
from 2.5 million flasks to 4.5 million flasks. The total 



Table 6. — Total resource availability 



Status 



Cost range 
per flask 



Total recoverable 
Hg, 103 
flasks 



Producers . . . 
Nonproducers 

Total 



$300 
600 


2,454 
2,607 


450 

600 

1,000 

1,700 


53 
1,882 
1,930 
1,954 


300 

600 

1,000 

1,700 


2,454 
4,489 
4,537 
4,561 



recoverable mercury from all evaluated properties, 4.6 
million flasks, is available at costs less than $1,700. 

Table 6 indicates that 2.6 million flasks of mercury are 
recoverable from producing properties at production costs 
ranging up to $600 per flask. Approximately 2 million flasks 
of mercury are recoverable from currently nonproducing 
properties at production costs ranging from $450 to $1,700 
per flask. ' 



ANNUAL AVAILABILITY 

Analyses were performed to estimate the potential an- 
nual production capabilities of producing and nonproduc- 
ing deposits. Production potential for nonproducing deposits 
was estimated based upon deposit size (demonstrated 
resources), past production history, and capacities of similar 
producing operations. Estimates of production potential at 
the given capacity levels for the next 15 yr are provided. 
Based upon these assumptions, an analysis of annual mer- 
cury availability is presented below. 

Figure 9 shows annual mercury availability from pro- 
ducing deposits. At a production cost of $600 per flask, ap- 
proximately 126,000 flasks of mercury are annually 
available between the years 1984 and 1988. This compares 



140 



130 



120 



no 



00 



90 



80 



•A 
\ 
\ 

'W 

\ \ 
\ \ 

w 

\ X. 

\ 

\ 



KEY 

$ 150 (Jan. 1984$) 
$ 300 (Jan. 1984$) 
< $600 (Jan. 1984$) 






I — 

1964 



'-.■-.f-. 



988 



1990 



1992 



1994 



1996 



1998 



2000 



Figure 9.— Annual availability from producing deposits at various prices. 



16 



90 



80- 



70- 



60- 



>- 
cr 

3 50 

UJ 



40- 



30 



20 



II 1 ■ 
N Year preproduction 
development begins 

--\ 
/ \ 

/ 


i l 1 1 

KEY 


"• $ «jOU \ Jan. lyoH .p/TiasKj 
< $ 1,700 (Jan. 1984 $/f lask) 

\\ 

NX 
NX 


\\ 

i i i 


1 1 1 1 



/V+2 



/V+4 



/V+6 



/V + 8 
YEAR 



/V+IO 



/V+12 



/V+14 



/V + 16 



Figure 10.— Annual availability from nonproducing deposits at various prices. 



with 103,500 flasks of mercury produced from market 
economy countries in 1983. By the end of 1992, production 
would decrease to 85,000 flasks of mercury per year, if 
resources from deposits having total production costs be- 
tween $500 to $600 per flask are depleted by the end of that 
year. This decrease may be offset if resources currently con- 
sidered inferred are further explored and proven, thereby 
increasing the demonstrated reserve base. From 1992 
through 2000, mercury availability remains stable at 85,000 
flasks per year. 

Similarly, approximately 114,000 flasks of mercury are 
available between 1984 and 1988 at a production cost of 
less than $300 per flask. This is sufficient to meet the 1983 
production rate of 103,500 flasks per year from market 
economy countries. Availability goes down to 80,000 flasks 
per year by 1990 and remains at this level until at least 
2000. Much of this decrease in primary mercury availability 
could be offset by increased sales from stockpiles or use of 
mercury from secondary sources. 

At the present mercury market price, deposits evaluated 
in this study supply approximately 59 pet of current world 
production of primary mercury. The remainder is supplied 
by centrally planned economy countries or countries with 
small production not evaluated in this study. In 1990, 
deposits considered in this study would only be able to pro- 
vide 34 pet of probable demand of 233,000 flasks (table 1). 
By 2000, only 27 pet of the probable demand (295,000 flasks) 
would be available from deposits with total production costs 
less than $300 per flask. Additional mercury resources 
would need to be defined at much higher production costs 
to meet the anticipated demand in 2000. 

Generally, nonproducing deposits have much higher 
production costs than producing properties. This is due in 
part to the higher investments that are required and to the 
generally lower ore grade. The average ore grade of non- 
producing deposits is approximately one third of that for 
producing deposits. Construction of annual availability 
curves for these nonproducing properties is based on the 
assumption that preproduction development would begin 



in the year N. Past experience indicates that 1 or 2 yr would 
be required from the year development begins before any 
production could occur. Annual availability of mercury from 
nonproducing deposits is shown in figure 10. No mercury 
from these deposits is available at the current market price 
of approximately $300 per flask, although one property has 
a production cost of less than $350 per flask and has the 
potential of recovering 7,200 flasks per year through year 
N+7 should market conditions merit its reopening. 

Most of the mercury from nonproducers can be recovered 
at costs ranging from $500 to $1,000 per flask. Approxi- 
mately 61,000 flasks become available in years N+2 
through N+5 at a production cost of less than $650 per 
flask, while a total of 69,000 flasks is available at costs less 
than $1,000 per flask for the same interval. Within the same 
period, for costs ranging from $1,000 to $1,700 per flask, 
an additional 6,000 flasks become available for a total of 
75,000 flasks at a cost of less than $1,700 per flask. 

Mercury available from nonproducing deposits 
decreases rapidly from years N+6 through N+9. At this 
point, only 30,000 flasks of mercury are available at costs 
less than $650 per flask. This quantity continues to be 
available until 2V+15, the last year of the analysis period. 

To meet anticipated future demand, additional mercury 
production is required to supplement those properties cur- 
rently producing. Assuming a demand of 233,000 flasks in 
1990, producing operations could potentially supply 36 pet 
at costs up to $600 per flask; deposits not currently produc- 
ing could supply an additional 30 pet at costs up to $1,000 
per flask. The remaining one-third would have to be sup- 
plied from either centrally planned economy countries, from 
Government or industry stockpiles, or from recycled 
mercury. 

Actual annual availability could vary from anticipated 
availability as market conditions change. Factors that 
would affect such a change include varied production of ex- 
isting mines, nonproducing deposits coming into production, 
discovery of additional deposits, and reclassification of in- 
ferred resources as demonstrated. 



17 



FACTORS AFFECTING AVAILABILITY 



Factors that could affect mercury availability are infla- 
tion, labor, and energy costs. These factors were analyzed 
to determine the magnitude of effect on mercury avail- 
ability. Based upon these analyses, the relative effect was 
very small. 

The effect of inflation on mercury availability is negligi- 
ble. A 25-pct increase in capital costs as a result of infla- 
tion results in a decrease in available mercury of 0.9 pet; 
a 50-pct increase results in a 2.4-pct decrease in available 
mercury at a cost of $1,000 per flask. At a total production 
cost of $600 per flask, a 10- or 15-pct increase in operating 
cost results in a decrease in availability of 22,000 flasks 
from a base of 2.6 million flasks; a 25-pct increase results 
in a decrease of 53,000 flasks at $600 per flask. 

The effects of changes in labor or energy costs on mer- 
cury availability were also found to be negligible. At $600 
per flask, mercury availability decreased 0.8 pet for both 
10- and 15-pct increases in labor costs. The effects of energy 
increases on mercury availability were similar to those for 
labor. 

Stockpiled and secondary mercury sources should also 
be considered in mercury availability discussions. Owing 



to mercury's limited sources of supply, many countries have 
considerable stockpiles of mercury, which may be used to 
meet internal mercury demand requirements should inter- 
nal supply or import problems arise. In the United States, 
for example, 12,786 flasks of mercury were imported in 1983 
while the U.S. stockpile contained 178,315 flasks (2). In the 
event of a total disruption of all imported sources of mer- 
cury, the stockpile, if maintained at the 1983 level, 
represents a potential 14 yr supply at 1983 levels to supple- 
ment domestic production. Currently, efforts are being made 
to reduce the mercury stockpile inventory to 10,500 flasks, 
an effort that influences both short- and long-term domestic 
supply patterns. 

Primary mercury price patterns also may significantly 
affect mercury recovery from secondary mercury sources 
(recycling and byproduct recovery). A significant increase 
in primary mercury price could result in increased recovery 
of mercury from secondary and byproduct sources. Current 
trends indicate, however, that the relative proportions of 
mercury recovery from primary and secondary sources 
should be relatively stable, barring any major changes in 
recovery technology or mercury prices. 



CONCLUSIONS 



There has been little change in mercury mining and 
processing technology in recent years. A greater change has 
occurred in mercury use patterns where technological 
changes in mercury battery design, more efficient chlor- 
alkali cells, and improvements in the substitute diaphragm 
cell have begun to reduce primary mercury consumption. 
Environmental concerns have provided impetus for more 
efficient recycling practices. Recycled mercury will un- 
doubtedly make up a significant portion of mercury supply 
in the future. 

The mercury industry appears to be stabilizing after a 
period of low demand and depressed market price brought 
about in part by increased environmental concerns and use 
of substitutes. Although prime virgin mercury consumption 
appears to be decreasing slightly, there are few indications 
that producers are curtailing output. Excess production 
from principal market economy countries is being stock- 
piled; most production from centrally planned economy 
countries is being consumed internally. At present, the $300 
per flask price appears stable. Production is reduced or cur- 
tailed for those operations that repeatedly incur costs above 
this level; a market price well above this level would 
encourage increased mercury production. 

Demonstrated in situ resources of mercury from market 
economy countries amount to approximately 25 million tons 
of ore from which 4.6 million flasks of mercury are poten- 
tially recoverable utilizing present technology. In light of 
prevailing economic conditions, it is estimated that these 
demonstrated resources could supply mercury at least un- 
til 2000 at proposed production levels. Mercury from pro- 
ducing properties operating at costs less than $600 per flask 
would be sufficient to meet market economy production 
needs at current production rates until 1988. Mercury 
availability could be greatly increased as known mercury 
occurrences, with identified tonnages containing over 17 
million flasks, are further explored and resources upgraded 
to the demonstrated level. Countries with the greatest 
future mercury potential include Spain, China, the U.S.S.R., 
Yugoslavia, Italy, and the United States (primarily Califor- 



nia, Nevada, and Alaska). 

Domestic mercury requirements will become much more 
dependent on foreign sources when the only domestic 
primary mercury producer exhausts its reserves within the 
next 5 to 8 yr. Demonstrated domestic resources are not suf- 
ficient to meet anticipated domestic demand; current pro- 
duction levels could only be maintained if (1) exploration 
work delineated additional demonstrated resources, (2) 
higher market price justified mining of low-grade, high-cost 
deposits, or (3) high environmental pollution control costs 
could be acceptable. It is unlikely that mercury prices will 
reach high enough levels to justify reopening or develop- 
ment of other domestic resources in the near future. 

Foreign dependency could be lessened through the use 
of mercury from Government and industry stockpiles and 
secondary sources. 

Approximately 2.5 million flasks, or 54 pet of the total 
available mercury, as determined in this study, could be 
economically recovered at the January 1984 market price 
of approximately $300 per flask from operating mines in 
Spain, Algeria, and the United States. If mercury costs 
reach $600 per flask, 96 pet of the total available mercury, 
or an additional 2 million flasks, would become available 
from producing and nonproducing deposits. 

Based upon forecast demand levels, assuming an annual 
growth rate of 1.4 pet, mercury from market economy coun- 
tries recoverable at a total production cost of $300 per flask 
would supply only 33 pet of total world demand in 1990. 
Market economy countries could supply only 29 pet of an- 
ticipated world demand by 2000. To meet demand re- 
quirements, additional properties would need to come on- 
line to supplement producers at higher mercury costs, or 
a greater percentage of mercury could be purchased from 
centrally planned economy countries. Mercury production 
from these countries has increased in recent years. These 
demand projections could change significantly, however, if 
the projected growth rate does not come about owing to a 
decrease in mercury demand. 



18 



REFERENCES 



1. Bailey, E. H., A. L. Clark, and R. M. Smith. Mercury. Ch. 
in United States Mineral Resources. U.S. Geol. Surv. Prof. Paper 
820, 1973, pp. 401-414. 

2. Carrico, L. C. Mercury. Ch. in Mineral Facts and Problems, 
1985 edition. BuMines preprint B 675, 1985, 10 pp. 

3. Clement, G. K., Jr., R. L. Miller, P. A. Seibert, L. Avery, and 
H. Bennett. Capital and Operating Cost Estimating System Manual 
for Mining and Beneficiation of Metallic and Nonmetallic Minerals 
Except Fossil Fuels in the United States and Canada. BuMines 
Spec. Publ., 1980, 149 pp. 

4. Davidoff, R. L. Supply Analysis Model (SAM): A Minerals 
Availability System Methodology. BuMines IC 8820, 1979, 45 

PP- 

5. Davis, F. F., and E. H. Bailey. Mercury. Ch. in Mineral and 
Water Resources of California. CA Div. Mines and Geol. Bull. 191, 
1966, pp. 247-254. 



6. Drake, H. J. Mercury. Ch. in Mineral Facts and Problems, 
1980 Edition. BuMines B 671, 1981, pp. 563-574. 

7. Mining Magazine (London). Almaden - World's Largest Mer- 
cury Mine. V. 118, No. 2, 1968, pp. 80-91. 

8. McDermitt Mine - the U.S.A. 's Largest Producer of 

Mercury. V. 146, No. 7, 1982, p.261. 

9. Pennington, J. W. Mercury. A Materials Survey. BuMines 
IC 7941, 1959, 92 pp. 

10. Placer Development Limited (British Columbia, Canada). 1983 
Annual Report, p. 29. 

11. U.S. Bureau of Mines. Mercury Potential of the United States. 
BuMines IC 8252, 1965, 376 pp. 

12. Mineral Commodity Summaries 1984. Mercury. 

January 1984, pp. 98-99. 

13. U.S. Geological Survey. Principles of a Resource/Reserve 
Classification for Minerals. U.S. Geol. Surv. Circ. 831, 1980, 5 pp. 



APPENDIX A 



Domestic deposits considered for evaluation but not in- 
cluded in this study since deposit selection criteria were not 



met are California— Buena Vista, Gambonini, Guadalupe, 
Knoxville, Mt. Jackson, and New Almaden; Texas— Fresno. 



APPENDIX B 



Numerous areas have either recovered mercury in the 
past or are reported to contain mercury. Although numerous 
occurrences are documented, deposits with demonstrated 
resources are rare. Domestic areas with significant mercury 
potential (11) that require additional exploration work to 
delineate resources are- 
Alaska: Bristol Bay region, Kuskokwim River region, 
Seward Peninsula region, Yukon River region. 

California: Adelaide district, Altoona district, Cambria- 
Oceanic district, Clear Lake district, East Mayacmas 
district, Guerneville district, Knoxville district, New 



Almaden district, New Idria district, Petaluma district, 
Stayton district, Sulphur Springs Mountain district, West 
Mayacmas district, Wilbur Springs district. 

Idaho: Valley County district, Washington County 
district. 

Nevada: Antelope Springs district, Fish Lake Valley 
district, Goldbanks district, Ivanhoe district, Opalite 
district, Union district. 

Oregon: Crook County district, Lake County district. 

Texas: Buena Suerte district, Terlingua district. 



i 






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